To help you see the impact you can have by cutting out a car journey or two check out our special UK Car-Free Map where you can calculate how much C02 you can save by walking, cycling or hopping on public transport rather than burning some rubber.

Will Durham go car-free for a day?Kris Murrin's third challenge is in Durham, which is in the top 10 of carbon footprints in the country, with the largest traffic increase in the north-east over the last decade.